Lapping machine construction



Sept. 29', 1953 R. G. RosHoNG ET AL 2,653,422

LAPPING MACHINE CONSTRUCTION Filed Aug. 23, 194s 2 sheets-sheet 1 gaa@ 777%- Sept 29, 1953 R. G. ROSHNG ET AL 2,653,422

LAPPING MACHINE CONSTRUCTION Filed Aug. 23, 1949 2 Sheets-Sheet 2 y Win/7"@ J 52 l w22 f. Z

Pa'tented Sept. 29, 19.53

UNITED iRaymond GeorgeRoshongfortlgHollywood, ',Vasalie'L. 4leickii, Hollywood, -Califa assignors to Crane Packing This invention relates to jan abrading A`and polishing machine and :particularly lto machines for lapping surfaces toa predetermined contour.

The principal object-of this invention is to proa lapping machine in which the lapping platen l of the machine and Athe abradant agitator used with the lapping platen are `driven by `'a unitary drive.

Another object of this invention is to provide a support for an abradant agitator which likewise performs the function of positioning the work holders, said support and work holders be'- ing so spaced as to provide a maximum freedom of operation for the work holders.

Yet another object of this invention is to provide a tripod type of support for a lapping ma:- chine, said tripod serving alsor to support the abradant agitating means as well as the work holders.

Yet another object of this invention is to provide a work holder for the work to be lapped', said holder serving also to maintain the lap in a true condition automatically.

These and other objects and features of this invention will become apparent from the fol; lowing detailed description when takeny together with the accompanying drawings, in which Y Fig. 1 is a side elevation partly insection` of a machine embodying the features of this' inven# tion;

Fig, 2 is a planviewof the machine shown in Fig. 1; Y

Figs. 3 and 4 are a section andV plan view, re'' spectively, of a holder to be used with the machine ofFigs. 1 and 2; and

Figs. 5 and 6 are alternative forms ofholders to be used with theusaid lappingv machine; I

Referring nowk to Figs. 1'V and 2 fora detailed description of theinvention,. there isvsliown a frame cross-member III which may bevcast otherwise formed to havea: flange: II- extending upwardly therefrom, said fiange II'being'en-j larged at I2, I3 and? I4- (l-igZ)-` to formfbos'ses' extending generallyA in a verticalrdirectionf viewed in Fig. 1.v Saidbosses `ar'e'drille'd tof-prog4 vide openings I5-througli-which extend rods-i6; forming the.` supporti for". crossernemb'er I- anlf the` rods are positioned.' axially'- with respect to` cross-member I 0 bymearis` of set JscrewsI-'Il which are threaded into :bosses I2; I3andil 4 and vs/"hich"v extend into blind .openingsy I 8in-said rods' t'o prie-A vent relative axial movementatherebetween.

It is apparent.that-thethree-rodsfwill provide`l npany, Chicago, Ill., a

'-Iihe'upperends I9 of the rods I6 extend into openingsj formed in another cross-member in the formof a spider 2'I having one arm for each of;the 'supporting rods I6. The openings litiga-re blind holes having a close t relative to :rods I6 so that the weightzo'f the cross-'member is sufficient to hold said spiderpn the ends of the -saidfsupporting rods. The central portion of the spider 2l is `formed'as'a receptacle 22 for retaining Vthe abradant V used in the lapping operation. -Said receptacle 22 has an opening 23 in the upper end thereof-through which the abradant is supfplied, While the machine is in operation the -abradant is continually agitated and pumped by a paddle 24whichmayzcomprise a strip of leather er rubber clamped between a pair of lugs 25 extending from a sleeve -26 mounted on a central shaft 3-2. Thesleeve 26jextends over the upper end of the said shaft 32 so as to be supported -thereby and is locked. to the shaft 32 by means of a set screw -28 which is'screwed at 29 into the upper end of said sleeve 26. An anti-friction packing ring 30 preferably of the type shown as an O-ring is interposed between the upper end of sleeve -26 and the end 3I of a journal formed integrallywith spider 2 I. It is contemplated that anti-friction packing ring 30 will prevent the abradant from splashing into the bearing. The level of the abradant in the receptacle 22 will be such thatl the abrasive in the abradant will not enter the bearing and accelerate the Wear thereof. l

The shaft 32 extendsV` downwardly into a bushing 33 Asupported ina centrally located boss 34 formed integrally with frame cross-member I0. Said bushing 33h'as a ange 35 which acts as a thrust member and supports the weights of the rotating parts ofl the machine with the exception of the motora'nd reduction gear as will be pointed out hereinafter.

Shaft 32 is loosely coupled to a shaft 36 forming the output member of a worm and Wheel typev speed'v reducer shown generally at 3l and dri-ven by. an' electricfm'otor' 38 which in turn isF supported from the underside of frame crossmem'ber I0'. Said cross-member Ill'- has an inverted, receptacle 39S' formedethe'r'ein opening on the. underside'V of-y the cross-member, said re-A ceptacle serving/ toi` support a sw-itch ddwhich controls-th operation'- of motor 387. y

Restinguponflan'g'e? 35 is a lapping platen 4'I` which Yfis-v circular 'in'AA plan ViewA and is provided With a'plur'ali-ty ofra'diaily disposed serrations 42, the function" ofwhich'is'wo receive" excess grit arid/abrasive| aslWell-vas the cuttings from the material being-lapped Other serrati'ons 'I3V are formed onC the Aundersidc-iof platen 4I to prevent the f abradantl from working its w'ay radially in;- Ward toA- the bushing 33,: The upperk surface 43 of said platen is initially formed to have the desmaller diameter than the inside diameterof flange Il so that a space 41 is formed therebe-- tween through which the excess abradant may fall into the additional space formedby frame cross-member itl and flange H. A boss `ifi-isl formed on cross-member Il! and drilled at 49 to provide an opening through which the collected abradant vehicle may be drained as the abra- 4 Y convex surface is formed thereon. Thus a surface having slight convexity, or slight concavity, or true fiatness can be generated and maintained by properly locating the holders radially of the platen 4I. This is brought about by the change in the amount of overhang of the holder relative to the outer or inner edges of the platen which, in turn, changes theunit pressure exerted by the holder at various .points on the platen. The unit sive suspended therein settles. Normallya drain plug 5t serves to hold the abradant in said crossmember I0. The settled abrasive can be removed from the said cross-member l by raising lapping platen lll. This is accomplished by pulling up sleeve 26 which in turn pulls up shaft 32 and platen 4| through screws 29 and 45 respectively. The loose coupling referred to above being comprised of a tongue 'Il on shaft 32 and a groove l2 in shaft 36, will separate to allow sleeve 25 to be pulled up.

Referring now to Figs. 3 to 6, inclusive, the work holders are comprised of substantially solid cylindrical blocks l having a tapered shoulder 52 on the cylindrical surface thereof. Each block has a blind hole l53 formed in the central part thereof on one side, and on the other side, a recess 54 having the general shape of the article to be lapped. For purposes of illustration, the article in the present instance is a blade for an electric shearing device and is substantially rectangular in shape. It has been found that shear blades out best when ground slightly concave or hollow. 1n the present instance, the lap platen 4l is perfectly flat, but the concave surface is formed in the shearing blade nevertheless by means of a pin 55 which presses upon the plate at an unsupported point thereon so that the blade is sprung from its normal shape to one slightly convex at the surface of the lapping plate. The force for springing the blade is supplied by a spring 55S energized by the weight of the holder, the pressure of the spring being controlled by a screw 5".' threaded into a suitable opening `58 in holder 5l.' Pin 55 is of smalier diameter than spring t and is provided with a head 59 which is adapted to abut on a shoulder '69 formed by the difference in diameters of the openings in which pin 55 and screw 5'! are disposed and which serves to limit the outward movement of the pin.

Referring again to Figs. 1 and 2, the holders 5I are held against revolution about shaft 32 with platen 4| by rods iii which are axially slidable in openings 52 in rotatable bushings 53. The openings 52 are eccentrically located with respect to the centers of bushings t3 as shown more clearly in Fig. 2 so that radial locations of the rods BI relative to the platen 'il may be controlled by turning bushings e3 in openings 'is in the spider in which they are supported. Said openings lli are disposed in bosses 75 in spider 2|, the bosses being equidistantly spaced between the arms of the spider 2l to avoid any interference between the work and the spider 2l. It has been found that the position of the holder relative to the lap platen fi! in a radial direction determines the nature of the surface generated by lap platen dl. rihus, by locating the holders at their innermost radial position, a concave surface is formed on lap platen M, and by locating the holders 5i at their outermost position radially of the platen il a pressure becomes` greatest at the point of o verhang and the wearconsequently becomes greatest at that point. If there is more overhang at the' outer edge ofthelap than at the inner edge, the' platen will become convex, and if there is more overhang at the inner edge, then the platen will become convex. At some intermediate point, the' wear will be uniform and a flat platen will result. The optimum position of the holders for any machine and article is best found by trial and error. The eccentric support for rod El therefore provides a simple means for adjusting the position of any one of the work holders operating on platen 4 l.

ft will be noted that three equally spaced worlr holders are provided which have been found to be the maximum usable number of work holders in a machine of the size herein disclosed. Since there are three supporting rods le, the use of three work holders results in a symmetrical clisposition of the work holders and supporting rods.

The holder shown in Figs. 5 and 6 is a double holder for lapping two blades simultaneously. These blades may likewise be rectangular in shape and are pressed on an unsupported part thereof by pins ed which are held against the blade by a spring 65, the pressure of which is controlled by a screw te.

The holders are removed from the lapping platen by sliding rods tl upward in the openings y52, the rods being bent at Gl to provide handles by which such movement can be effected.

The abradant is fedV from the receptacle 22 to the tapered shoulder 52 on one of the work holders by means of a valve 38 which communicates with the interior of the receptacle through an opening to and allows the abradant to drip onto a trough 59 from which it is fed by a wire 'it to the said taper 52. It has been found that due to the curvature of the wiper 2t, a small amount of the abradant will be trapped in the opening 8d and will be forced out of the opening and into the trough, thereby maintaining the opening free of accumulative abrasive.

In operation, switch di? is turned to start motor 33 whereupon the drive from the motor is transmitted through the reduction gearing E? to shaft 3s and thence to shaft 32. The rotation of shaft 32 is in turn transmitted to lap platen ii through the pin ed and to the abradant agitating paddle 2li. and sleeve 2t through pin 28. The rotation of the platen automatically induces the rotation of Veach of the work holders resting thereupon. v The rotation of the workY holders in turn causes a lrotation of the blades held therein so that the` formation of a pattern on the 'lap v surface is substantiallyY avoided. The localized pressure provided by the pins 55 and causes the lapping operation to be concentrated on those portions of the blades which are immediately adjacent the unsupported section, and since those portions are disposed inwardly of the edges cf the blades, the resultant surface on the blades is concave when the spring pressure is released and the blades are removed. VSimultaneously with the rotation of` the `lap plate,A the valve 68 is.

opened to permit the abradant to drip upon trough 59 and then pass along wire 10 to the taper 52 on the work holder. IOn taper 52 the abradant passes over the sides of the work holder by gravity to the lap platen where the rotation of the platen and work holder causes an even distribution of the abradant over the surface of the platen. The lapping process continues automatically until the blades are deemed to be completely lapped, whereupon the switch 40 is turned the opposite way to stop the motor and the rotation of the lap platen and paddle is likewise halted. After the lap platen 4l has stopped, rods 6l are withdrawn from their respective openings 53 to free the work holders and. the work holders are then removed to permit the exchange of an unlapped blade for the lapped blade thereon.

It is understood that the weight of each work holder 5I is effective to cause the work holder itself to wear the surface of the platen. This wearing action by the work holder is preferably so arranged that the work holder will wear the platen faster than the work itself and since the work holders may be adjusted radially of the platen, any desired surface contour can be maintained for long periods of time by the work holders.

It is believed that the simplicity of the construction of the abrading and polishing machine described above is apparent both from the drawings and description and hence need not be elaborated upon further. The machine is highly adaptable to various work holders, and because each part of the machine is made to perform a multiplicity of functions, the cost of the machine is maintained at a minimum.

It is understood that the foregoing description is illustrative of preferred embodiments of this invention and that the scope of the invention is not to be limited thereto, but is tobe determined by the appended claims.

What is claimed is:

1. A machine for finishing surfaces of articles, said machine comprising a platen, a machine frame for supporting the platen, a shaft passing through and secured to the platen, an abradantsupplying device, means on the frame for supporting the abradant-supplying device over the platen, a paddle in the abradant-supplying device, a sleeve secured to the shaft and to the paddle, a receptacle disposed below the platen for receiving excess abradant from the platen, means secured to the machine frame for driving the shaft, and an axially slidable driving connection between the shaft and the said shaft driving means, whereby said shaft, platen, sleeve and paddle may be raised from the receptacle to provide access to the said receptacle for cleaning purposes. g

2. A machine for finishing surfaces of articles comprising a rotatable platen for operating upon the articles to be nished, an abradant-supplying device, and a frame for supporting the platen and abradant-supplying device, said frame comprising a cross-member having a plurality of arms, each arm having a socket substantially at the end thereof, supporting legs comprising rods extending into said sockets, a second cross-memy platen, said motor being supported from the second cross-member. Y

3. A machine for finishing surfaces as de- 6 scribed in claim 2, said first-mentioned crossmember having bosses, one disposed between each pair of arms, and means mounted in said bosses for holding the articles on the platen.

4. A machine for finishing surfaces of articles comprising a rotatable platen for operating upon the articles to be finished, a frame spaced from said platen, rotatable conditioning rings cooperating with the platen to maintain a desired surface on the latter, and means on the frame for holding the axes of the rings stationary relative to the frame, said holding means including a rotatable support for each ring and having an eccentrically disposed opening therein, and a pin disposed in each opening and extending into the ring so that each ring is rotatable about-the axis of the pin, means for adjusting the angular position of each rotatable support, an abradantsupplying device on the frame disposed centrally of the platen, said frame including arms radiating from the abradant-supplying device, and means cooperating with the ends of the arms for holding the frame spaced from the platen, said holding means including bosses disposed between the arms and having openings to receive the said rotatable supports.

5. A machine for finishing surfaces of articles comprising a rotatable platen for operating upon the articles to be finished, a frame spaced from said platen, rotatable conditioning rings cooperating with the platen to maintain a desired surface on the latter, and means on the frame for holding the axes of the rings stationary relative to the frame, said holding means including a rotatable support for each ring and having an ec centrically disposed opening therein, and apin rdisposed in each opening and extending into the ring so that each ring is rotatable about the axis of the pin, means for adjusting the angular position of each rotatable support, an abradantsupplying device on the frame disposed centrally of the platen and including a receptacle and a paddle Within the receptacle, said frame including arms radiating from the abradant-supplying device, means cooperating with the ends of the arms for holding the frame spaced from the platen, said holding means including bosses disposed between the arms and having openings to receive the said rotatable supports, and a common drive shaft for the paddle and platen.

RAYMOND GEORGE ROSI-IONG. VASALIE L. PEICKII.

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